In a vehicle such as an automobile, a wiper apparatus is provided to ensure a visual field of a driver by wiping attached matters such as rain, snow, bugs, or droplets from preceding cars, which have been adhered on a windshield glass such as a front glass. The wiper apparatus generally has a wiper arm swung by an electric motor and a wiper blade attached to a tip portion of the wiper arm, wherein a wiping operation is conducted by the wider blade reciprocating on the windshield.
As the wiper blade used in such a wiper apparatus, there has been known the wiper blade in which the blade rubber directly contacting with the front glass is directly attached to a flat leaf spring member formed of an elastic member such as a steel plate, for example, as shown in Japanese Patent Laid-Open Publication No. 6-340249. In this case, the flat leaf spring member is formed to curve at a curvature radius smaller than that of the front glass, so that the flat leaf spring member is elastically deformed by a pressing force applied from the wiper arm to disperse the pressing force in a longitudinal direction of the blade rubber.
In such a wiper blade, however, the flat leaf spring member is formed with a longitudinal dimension equal to that of the blade rubber and into a curved shape, so that when the wiper blade with a blade length of, for example, 700 mm or so is manufactured, the flat leaf spring member becomes lengthy accordingly. Therefore, it is feared that: when the flat leaf spring members are carried into a work site, their returnable boxes grow in size; due to decreasing of the packed number of them or the like, efficiency in physical distribution aspects is lowered; and when the flat leaf spring members are processed, they are deformed due to interference with a die or molding machine in some cases. That is, handling them has not been easy.
Furthermore, the windshield glasses provided to the vehicles often have different curvatures depending on types of the vehicles due to their design or the like. In contrast, since a distribution pressure of the blade rubber to the windshield glass is determined based on a characteristic of the flat leaf spring member in such a wiper blade, the wiper blade using the flat leaf spring member with a predetermined characteristic can generate a distribution pressure effective on only a windshield glass with a specific curvature. Accordingly, since the wiper blade using an exclusive flat leaf spring member is set for each vehicle type, it becomes necessary to prepare various kinds of flat leaf spring members different in characteristic, so that manufacturing the wiper blades different in characteristic has become complicated.
An object of the present invention is to facilitate the manufacturing of the wiper blade.
Another object of the present invention is to make it easy to manufacture the wiper blades different in characteristic.